Slack adjuster



June 23, 1970 J. w. KA\M SLACK ADJUSTER Filed Aug. 21, 1968 United States Patent 3,516,696 SLACK ADJUSTER John W. Kaim, Chicago, Ill., assignor to Amsted Industries Incorporated, Chicago, Ill., a corporation of Delaware Filed Aug. 21, 1968, Ser. No. 754,263 Int. Cl. F16b 7/06 US. Cl. 287---61 3 Claims ABSTRACT OF THE DISCLOSURE A manual slack adjuster usable to adjust railway brake rigging has the threaded end of a screw engaged with a helicoid secured to the interior of a tube and is aligned therewith by a bushing. A cover secured to the screw telescopes over the tube and has an annular scraper contacting the tubes outer surface. Rotatably fastened to the opposite end of the tube by bolts contacting an annular groove is a. cup-like jaw having a pivotal hinge lock that is engageable with a gripping area on the tube to rotatably lock the tube to the jaw. The jaw and screw are pivotally engageable with railway brake levers.

This invention relates to slack adjusters, particularly manual slack adjusters for railway brake rigging.

An object of this invention is to provide a manual slack adjuster for railway brake rigging which is usable to compensate for brake shoe and wheel wear.

Another object of this invention is to provide an inexpensive slack adjuster that may be easily repaired.

A further object of this invention is to provide a slack adjuster that cannot be accidentally adjusted.

The foregoing and other objects and advantages of the invention will become apparent from the following description and accompanying drawings wherein:

FIG. 1 is a semi-schematic view illustrating a railway truck having brake rigging;

FIG. 2 is a top plan view illustrating a slack adjuster;

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2; and

FIG. 4 is a sectional view taken on line 44 of FIG. 3.

Referring now to the drawings, FIG. 1 illustrates a railway truck 6 supported by wheels 8 and 10. Brake rigging 12 is mounted on the truck 6 and includes a pneumatic cylinder 14 that is rigidly secured to the truck 6. The cylinder 14 is pivotally connected through a cylinder lever 15 to the upper end of a live lever 16. A slack adjuster 18 is pivotally connected to the lower end of the live lever 16 and to the lower end of a hanger lever 20 that is pivotally suspended from the truck 6. A brake lever 22 is pivotally suspended from the truck 6 and has its lower end pivotally connected to a brake head 24. The levers 16 and 20- are respectively pivotally connected intermediate their ends to brake heads 24 and 26. Brake shoes 25 and 27 are respectively secured to the brake heads 24 and 26 and are engageable with the wheels 8 and 10.

In operation, the cylinder lever 15, actuated by the cylinder 14, pulls the upper end of the live lever 16 to the left in FIG. 1 engaging shoe 25 with wheel 8. The lower end of lever 16 moves to the right forcing the slack adjuster 18 to move the lower end of hanger lever 20 to the right pivoting lever 20 and engaging shoe 27 wtih wheel 10.

The slack adjuster 18 that is illustrated in FIGS. 2-4, comprises a coupling member in the form of a screw 28 having a bifurcated end 30 and a threaded portion 32. The portion 32 is threadedly engaged with a helicoid insert 34 secured to one end of a rotatable member in the form of tubular housing 36. An aligning collar or bushing 38 secured to the end of the threaded portion 32 of the screw 28 is retained by a Washer 40 and a retaining ring 42. The bushing 38 is engaged with the interior of the tube 36 and aids in maintaining alignment of the screw 28 and tube 36.

The unthreaded end 44 of the tube 36 projects into a cup-like portion 46 of a coupling connector jaw 48 having a bifurcated end 50 and is rotatably engaged therein. Upper and lower bolts 52 and 54 are mounted proximate their ends in the jaw 48 and are slidably engaged with an annular groove 56 on the outer surface of the tube 36 to permit rotational movement between the tube 36 and jaw 48. Engagement of the bolts 52 and 54 and the groove 56 prevents longitudinal movement between the jaw 48 and the tube 36. These bolts may be retained by nuts 58.

The tube 36 includes a gripping area 60, illustrated as a hexagonal nut, proximate the open end of the cuplike portion 46 of the jaw 48. A hinge lock 62 straddles the jaw 48 and is pivotally secured thereto by the upper bolt 52. The inner surface 63 of the hinge lock 62 mates with the hexagonal nut portion of the tube 36 thereby maintaining the tube 36 and jaw 48 in a fixed rotational relationship.

A tubular cover 64 may be used to keep contaminates away from the threads 32 and 34 and retain lubricant. This cover 64 may be secured at one end to the screw 28 by a hose clamp 66. The other end of the cover may be sealed by a Wiping means in the form of a scraper slidably engaging the tube 36, and a hose clamp 72. The wiping means, as illustrated, seals one end of the cover 64 and removes foreign particles on the exterior of the tube 36 during adjustment of the slack adjuster 18.

Referring now to FIG. 1, as the brake shoes 25 and 27 wear, the cylinder must pull the live lever 16 further and further to the left to engage both brake shoes. This wear may be compensated for by pivoting the hinge lock 62 upward and turning the hexagonal nut portion 60. By turning the nut portion 60, the unthreaded end 44 of the tube 36 rotates in the jaw 48. Since the ends 30 and 50 are fixed, the end 30 of the screw 28 moves either away from or toward the tube 36 depending upon the tubes rotational movement. Once the proper length of the slack adjuster 18 is set, the hinge lock 62 is re-engaged with the gripping area 60. This re-engagement prevents rotation of the tube 36 and further adjustment of the slack adjuster 18.

It is to be understood that the foregoing description and the accompanying drawings have been given only by way of illustration and example. It is also to be understood that changes in form of the elements, rearrangement of parts, and substitution of equivalent elements, which will be obvious to those skilled in the art, are contemplated as within the scope of the present invention.

What is claimed is:

1. A slack adjuster comprising: a housing having a longitudinal open end chamber; threads in said chamber proximate an open end; a coupling connection screw threadedly engaged with said threads; means for maintaining alignment of said screw and said chamber; means for protecting said threaded engagement from contaminates; a coupling connection jaw rotatably engaged with said housing longitudinally distal from said threads in said chamber; means for interlocking the jaw and housing against movement lengthwise of the housing; a gripping area on said housing; and a lock pivotally secured to said coupling connection jaw, said lock being mateably engageable with said gripping area.

2. The slack adjuster set out in claim 1 wherein said means for protecting said threaded engagement comprises a telescoping cover secured to said screw and partially enclosing said housing; and Wiping means interengaged between said housing and said cover.

3. The slack adjuster set out in claim 1 wherein said coupling connection jaw is cup-like and is rotatably engaged with the periphery of said housing and said means for interlocking comprises a groove encircling the periphery of said housing, a passage projecting through said coupling connection jaw and communicating with a portion of said groove, and a bar projecting through said passage, said bar being engaged with said groove.

References Cited UNITED STATES PATENTS Flesch 287-61 Gothberg 28759 Sawyer 28760 XR Dorey 28760 Buvelot 28759 Sweetland 28760 XR Bosch 28762 Gibney 28762 XR DAVID J. WILLIAMOWSKY, Primary Examiner A. KUNDRAT, Assistant Examiner 

